We've been doing walkways, and patios now for a few years now and have been taking as many training courses, and classes as possible since then. Its been preached that anyhting over 4' must be engineered and in some cases walls as high as 3 foot may also require engineering. Forunately we have not had any of these cases, but I expect we will with time. How does one go about finding an engineer to do this? We are located in the Baltimore area, more specifically, GLen BUrnie. Generally speaking, how does this process work, and what sort of costs are involved? Thanks.